Manchester City midfielder Yaya Toure says that Chelsea are like a "wounded animal" and should not be underestimated by their upcoming opponents.
Jose Mourinho's side slumped to their ninth defeat in the Premier League this season when they lost 2-1 at Leicester City on Monday.
That result means the defending champions are 16th in the table -- just one point above the relegation zone -- having picked up only 15 points from their opening 16 league games, while such poor form has led to renewed speculation about Mourinho's job.
City are in much better shape in third, but Toure, 32, believes it is only a matter of time before Chelsea turn things around.
"In general I don't like talking about my opponents too much but it's obvious that at the moment it's not the real Chelsea that we see playing every week in the league," Toure told France Football.
"They're unrecognisable. They have too many problems -- both defensively and in their attacking efficiency -- for it to reflect their true level. I think all the great players go through a period where nothing works. It happens to everyone. You'd say that they have a massive lack of confidence.
"But since over there there are really great players and a really great manager, it would be a major error to consider that they're already beaten or are resigned [to defeat]. Watch out, Chelsea are a wounded animal. You have to be wary of that."
While they have struggled in domestic competition, Chelsea still managed to top their Champions League group ahead of Dynamo Kiev, Porto and Maccabi Tel-Aviv.
They were handed a tough draw in the round of 16 on Monday, however, and will face Paris Saint-Germain away in the first game of a two-legged tie on Feb. 16.
Many observers have already installed PSG as favourites to reach the quarterfinals, but Toure says the French champions will have a battle on their hands.
"It's not going to be as easy for PSG as some people would like to think," he said. "I'm even certain that Chelsea will have a whole new face next spring. From then until now, have confidence in Mourinho as well to wake them all up. Nobody will be sleeping against PSG.
"At the moment it's clear that PSG, who every English club wants to avoid, seem better than Chelsea. They're quite an impressive team -- perfectly organised. But in three months a lot of things can happen in the two camps."